Furnace-wall construction



April 30, 1929. B. SCHROEDER FURNACE WALL CONSTRUCTION Filed Sept. 11. 1924 ZZZ/62725;: gem/lard ficfiroeden Patented Apr. 30, 1929.

UNITED STATES IBERNHARD scnnommn, on CHICAGO, ILLINOIS.

FURNACE-WALL CONSTRUCTION.

Application filed September This invention relates to refractory wall structures and finds particular application in the construction of walls for the combustion chambers of furnaces.

In various refractory wall structures, for example in the walls of furnaces designed for the burning of pneumatically-fed pulverized fuel, it is frequently desirable to provide for the admission of air into the combustion chamber through the wall at various locations. In the consumption of pneumatically-fed pulverized coal, for example, apparatus now in use is calculated to supply up to 35% of the air requisite for combustion of the fuel incident to the feeding thereof. The balance of the combustion air must ,be fed or admitted to the combustion chamber apart from the injection of air used in introducing the fuel. The fuelfeeding nozzles customarily are arranged at the top of the combustion chamber, which latter is of substantial height, so as to afford an extensive space for the travel of the pulverized fuel incident to its combustion. It has been found of advantage to supply the additional combustion air through numerous ports distributed over the areaeof one or more of the furnace walls. In the more advanced design of such installations, provision is made for the preheating and the control of this additional air by the arrangement of a sheathing wall or insulating wall disposed exteriorly of and spaced from the refractory Wall so as to afford an intervening air chamber having communication with the interior of the combustion chamber through a number of ports in the refractory wall. Admission of air into the air chamber is controlled by suitable means and when admitted thereto receives a certain amount of preheating before its passage through the ports. For obvious reasons it is desirable that the insulating or sheathing wall be as light and as thin as circumstances will allow. For the fulfillment of its intended purpose it is not necessary that it be designed to withstand high temperatures, as it is one of the particular functions and purposes of the refractory wall to confine the heat to the combustion chamber;

In certain advanced designs of furnace structure of this general type, metallic members are utilized for supporting the refrac- .tory 'wall and the sheathing Wall. Sometimes also it is desirable to have but limited 1 1, 1924. Serial No. 737,020.

space between the two walls. Such circumstances, as well as other considerations, have led to the desirability of affording the sheathing wall and the metallic supporting members protection from radiant heat, and for providing a certain amount of interior ventilation for the refractory wall.

The general purpose of this invention is the provision of a wall construction which will permit free and distributed admission of air through it, yet effectively prevent the passage of radiant heat directly outward from the combustion chamber, and minimize the indirect transmission of radiant heat through the wall.

Another object is the provision of an improved wall construction designed for the admission of combustion air and arranged to effect equalization of the passage of air through it, so that comparative uniformity of temperature may be maintained in its component refractories.

A further object is the provision of interior ventilation for the refractory wall, with the object of limiting the temperature which it will attain in operation of the fur nace.

A still further object is the provision of a wall construction having the attributes above specified and which does not require 85 excessive thickness in the structure, which will accommodate expansion and contraction of its component -elements without warping or bulging or causing displacement of the refractories, which may be constructed economically and repaired with comparative ease.

Another object is the provision of a novel structural element for refractory furnace wall construction by the use of which refractory walls may be provided with air inlet ports which are effectively baffled against the passage of radiant heat.

Other and further objects of the invention will be pointed out hereinafter, indi- 100 cated in the appended claims, or obvious to one skilled in the art upon an understanding of the disclosure.

For the purpose of this application I have elected to illustrate and describe but a sin- 105 gle structural embodiment of my invention.

It is to be understood,-however, that this is presented for the purpose of illustration, and hence is not to be accorded any interpretation which may have the effect of lim- 110 iting the invention which I claim, short of its true and most comprehensive scope in the art.

In the drawing forming a part of this specification,

Fig. 1 is a part elevational view of the interior of a furnace wall;

Fig. 2 is a part sectional elevation of the same on the planes indicated by the lines 22 of Fig. 1, and

Fig. 3 is a cross-section of a portion of the wall structure 011 the planes indicated by the lines 33 of Fig. 1.

The nature of the invention will be most readily understood by reference immediately to this illustrative embodiment. Let it be understood that the reference character 10 designates structural members suitably supported to afford a framework for sustaining the furnace wall structure. Upon these are suspended the metallic hangers 11, each of which supports a vertical tier or stack of the refractories which form the furnace wall, said refractories finding support on the shelf 11 forming a part of the hanger. The frame members 10 support an insulating or sheathing wall disposed exteriorly of the refractory wall and spaced therefrom to afford an intervening air chamber; A portion of this sheathing wall is designated 12. This is most conveniently made of light material, such as gypsum tile, and is sheathed externally, for the purpose of protection and appearance, by a thin cover of plate 14.

As will be seen in Fig. 1, the hangers 11 are disposed in series running horizontally, at intervals such that the lateral faces of the tile on juxtaposed hangers are in abutment. The refractories 15 are of the conventional rectangular form with straight, parallel, lateral sides and with centrally arranged T-slots for engagement with the retaining flanges of the hangers 11. The maximum transverse dimension of the refractories 16 and 17 is the same as that of the refractories 15, namely, the full course width. The refractories 16 and 17, however, have portions of reduced width, so that their lateral margins are offset to afford laterally projecting spacing portions 16 and 17 The refractories l6 and 17, like the refractories 15, are provided with medial T-shaped end slots for engagement with the hangers. The refractories 16 have their reduced portion at the slotted end, while the refractories 17 have their reduced portion at the end opposite the slot, and the extent of the reduced portions of the refractories 16 and 17 is such that said portions overlap when the refractories are placed with their slotted ends in alignment. The refractories l6 and 17 are stacked on the hangers in alternate relationship, and in the same order on j uxtaposed hangers, so that horizontal courses of refractories 16 alternate with horizontal courses of refractories 17. Inasmuch as the normal-width spacing portions 16 and 17 of the refractories are in abutment, the reduced portions leave channels extending through the wall, both horizontally and vertically. The horizontal channels, however, do not extend directly through the wall, but are offset or diverted vertically, so that the portions 18, which open directly into the combustion chamber, are bafiled at the rear by the lateral spacing portions 17 of the refractories 17, while the channel portions 18*, which open into the air chamber,

are baffled from the furnacechamb'er by the portions 16 of the refractories. 16. This prevents the direct passage of radiant heat from the combustion chamber into theair chamber and hence affords protection to the metallic members 10 and 11 and the insulating wall 12. The overlapping of the reduced portions of the refractories 16 and 17 affords communication between the channel portions 18 and 18 and, where the wall structure is composed of alternate courses of those' refractories, affords vertical air passages in the wall which equalize the passage of air through the inlet channels and distribute circulation of air among the refractories, all of which tends to equalize the temperature of the several refractories and to exercise a cooling influence. The equalization of temperature of the refractories makes for equal expansion and contraction, and the intimate distribution of air through the refractories tends to prevent the destructive effects of extreme temperatures.

As seen inFig. 1, the hangers in adjacent horizontal series are arranged in staggered relationship, thus bringing the ports in one horizontal section of the wall in offset relationship to the ports in the sections above and below it. This makes for a more uniform distribution of the inducted air.

I claim: v

1. An element for furnace wall structure, consisting of complementary refractories each having an anchor slot at one end and a laterally reduced portion for a part of its length, said refractories being of substantially uniform length and of approximately the same width at their widest portions, the laterally reduced portion of one of the complementary refractories being toward the slotted end and of the other toward the opposite end.

2. An element for furnace structure, comprising mating T-shaped refractories of substantially equal maximum width and each having a support-engaging slot at the middle of one end, one of the mating refractories having a laterally reduced portion toward the slotted end, and the other refractory having a laterally reduced portion toward the end opposite its slot, said reduced portions being of-sueh length as to overlap arranged in horizontal courses with their full width portions in abutment and the reduced portions of refractories in juxtaposed courses towards opposite sides of the wall, and retaining members cooperating with the anchorage engaging portions to anchor the refractories against displacement horizontally.

4. In a furnace, a combustion chamber wall comprising refractories arranged to afford intervening air inlet channels extending through the wall from side to side and air-conducting passages extending vertically within the wall and connecting different inlet channels, and anchoring members holding the refractories against displacement horizontally into said inlet channels and airconducting passages.

5. A furnace wall comprising superimposed horizontal courses of refractories with the refractories in respective courses arranged edge to edge, certain of the refractories being spaced apart to afford intervening air admission channels extending through the wall and closed at top and bottom by other refractories, said channels having a tortuous course in the wall to direct passage of radiant heat through them, and anchoring members retaining the refractories against horizontal displacement, to maintain the form of the channels.

6. In furnace construction, the combination with an outer wall, of a furnace chamber wall made up of independently supported wall sections collaterally disposed and each comprising a plurality of refractories arranged one above another, refractories in juxtaposed sections being spaced to afford intervening air admission channels through the chamber wall, portions of refractories within the chamber wall being arranged to bathe direct passage of radiant heat through the-admission channels, and anchoring members retaining the refractories against horizontal encroachment on the channel areas.

7. In furnace-construction, the combina tion with a wall-supporting frame, of a furare arranged and built up of refractories arranged in nace wall disposed at the side of the frame superimposed courses, saidwall having air admission channels therethrough between refractories and debouching toward the frame, said admission channels having a tortuous course within the wall to bathe direct passage of radiant heat through them from the furnace chamber to the frame, and retaining members anchoring the refractories to the frame and retaining them against displacement horizontally into the 1 channel areas.

8. In a furnace, an upright wall built up of refractories arranged in superimposed and collateral relationships with air admission channels extending through the wall between some of the collaterally associated refractories, said channels having a tortuous course through the wall to baffle direct passage of radiant heat, and members anchoring the refractories against shifting into the channel areas.

9. In furnace construction, the combination with an outer wall, of a furnace chamber wall spaced therefrom to afford an intervening air passage, said chamber wall built up of refractories arranged in superimposed courses and having air admission channels between refractories in respective courses for conducting air from said air passage into the furnace chamber, said admission channels having a tortuous course'within the chamber wall to bathe direct assage of radiant heat through them from t e furnace chamber to the outer wall, and anchoring members retaining the refractories against displacement horizontally into the channel areas.

10. As an article of manufacture, a furnace wall refractory of uniform thickness and having its broader faces parallel and a T-shaped anchorage slot extending through one end perpendicularly to said faces, said refractory having full width portions and portions of reduced width so as to afford a tortuous air channel when assembled in collateral and superimposed relationship wlth other refractories.

In testimony whereof I have hereunto signed my name. I

BERNHARD SGHRQEDER. 

